MRI contrast using synthetic pulse sequences

1 . A method for generating a magnetic resonance image, comprising:

acquiring a first inversion recovery signal using a first inversion time;

acquiring a second inversion recovery signal using a second inversion time;

performing mathematical operations on the first inversion recovery signal and the second inversion recovery signal by applying Bloch equations to generate a plurality of synthetic divided subtracted inversion recovery (dSIR) or synthetic BipoLAr Inversion Recovery (BLAIR) image data sets with a plurality of different inversion times, wherein the Bloch equations are used to generate the plurality of synthetic dSIR or synthetic BLAIR image data sets;

generating synthetic dSIR images based on the plurality of synthetic dSIR or synthetic BLAIR image data sets; and

generating synthetic reversed dSIR (drSIR) images based on the plurality of synthetic dSIR or synthetic BLAIR image data sets.

2 . The method of claim 1 , further comprising:

generating a T1 map based on one of the synthetic dSIR image data sets within its middle domain (mD) from the plurality of synthetic dSIR image data sets; and

using a phase difference between the inversion recovery signals to disambiguate T1 maps outside the mD of the plurality of synthetic dSIR image data sets.

3 . The method of claim 2 , wherein generating the synthetic dSIR image comprises:

generating the synthetic dSIR image from the T1 map by applying a bipolar filter to generate high-contrast images from the T1 map free of signal saturation at selected signal levels; and

using a tissue property map to generate the synthetic dSIR image or the synthetic drSIR image with freely selected inversion times.

4 . The method of claim 1 , wherein performing the mathematical operations includes:

generating a logarithm of subtracted inversion recovery (lSIR) images produced from two inversion recovery images with different inversion times;

using an inverse hyperbolic tangent on the plurality of synthetic dSIR image data sets to generate a logarithm of the subtracted inversion recovery (lSIR) images; and

using T1 tissue property maps to generate synthetic lSIR images with a plurality of different inversion times.

5 . The method of claim 1 , wherein one or more of the plurality of synthetic dSIR image data sets exhibits whiteout, grayout, or bubble signs.

6 . The method of claim 1 , wherein synthetic BLAIR images with a plurality of inversion times are produced using Bloch equations from (i) the two inversion recovery images from directly acquired dSIR or drSIR images, and/or from (ii) T1 maps and/or other tissue property maps.

7 . A method of generating a magnetic resonance image, comprising:

obtaining at least one of a T1 map, T2 map, T2* map, perfusion map or D* map of a subject; and

applying a bipolar filter to the at least one obtained map to create a plurality of synthetic BipoLAr Inversion Recovery (BLAIR) images with a plurality of different inversion times, wherein creating the plurality of synthetic BLAIR images includes applying one or more signal models derived from Bloch equations to the at least one obtained map.

8 . The method of claim 7 , further comprising providing a gadolinium-based contrast agent or magnetic iron oxide particles to the subject.

9 . The method of claim 7 , wherein the plurality of synthetic BLAIR images with the plurality of different inversion times exhibit increased sensitivity to paramagnetic effects of molecular oxygen.

10 . The method of claim 7 , wherein the at least one of the T1 map, T2 map, T2* map, perfusion map or D* map is used with manipulation of blood longitudinal magnetization by slice-selected and non-slice-selected inversion pulses to visualize blood flow and/or perfusion.

11 . The method of claim 7 , wherein the plurality of synthetic BLAIR images with the plurality of different inversion times are used to demonstrate signal changes or T1 changes induced by intentional or incidental Magnetization Transfer (MT) pulses.

12 . The method of claim 7 , further comprising applying a bipolar filter to a phase map to amplify contrast in selected tissue property domains of the subject.

13 . The method of claim 7 , wherein one or more of the plurality of synthetic BLAIR images exhibit whiteout, grayout, or bubble signs.

14 . The method of claim 7 , further comprising mathematically combining two or more images of the plurality of synthetic BLAIR images to generate another image with different contrast.

15 . A method of generating a functional magnetic resonance imaging (fMRI) image, comprising:

acquiring a series of synthetic divided subtracted inversion recovery (dSIR) images with T2* sensitization during a functional task, wherein the series of synthetic dSIR images is synthetically generated using Bloch equations and has a plurality of different inversion times;

analyzing the series of synthetic dSIR images to identify a region of signal change corresponding to brain activation; and

generating at least one synthetic fMRI image corresponding to the identified region of signal change, wherein the at least one synthetic fMRI image exhibits increased sensitivity to both perfusion and Blood Oxygen Level Dependent (BOLD) effects.

16 . A method for generating bipolar filter magnetic resonance images using Multiplied, Added, Subtracted and/or Divided Echo Acquisition (MASDEA) sequences, including:

acquiring at least two echo acquisition signals;

performing mathematical operations using Bloch equations on the at least two echo acquisition signals, wherein performing mathematical operations includes at least one of multiplication, addition, subtraction, and division, and wherein performing the mathematical operations includes applying one or more signal models derived from the Bloch equations to the at least two echo acquisition signals; and

generating a synthetic image data set based on the performed mathematical operations to visualize iron-containing tissues with increased sensitivity.